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/*
* PowerPC atomic operations
*/
#ifndef _ASM_PPC_ATOMIC_H_
#define _ASM_PPC_ATOMIC_H_
typedef struct { volatile int counter; } atomic_t;
#ifdef __KERNEL__
#define ATOMIC_INIT(i) { (i) }
#define atomic_read(v) ((v)->counter)
#define atomic_set(v,i) (((v)->counter) = (i))
extern void atomic_clear_mask(unsigned long mask, unsigned long *addr);
#ifdef CONFIG_SMP
#define SMP_SYNC "sync"
#define SMP_ISYNC "\n\tisync"
#else
#define SMP_SYNC ""
#define SMP_ISYNC
#endif
/* Erratum #77 on the 405 means we need a sync or dcbt before every stwcx.
* The old ATOMIC_SYNC_FIX covered some but not all of this.
*/
#ifdef CONFIG_IBM405_ERR77
#define PPC405_ERR77(ra,rb) "dcbt " #ra "," #rb ";"
#else
#define PPC405_ERR77(ra,rb)
#endif
static __inline__ void atomic_add(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%3 # atomic_add\n\
add %0,%2,%0\n"
PPC405_ERR77(0,%3)
" stwcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (a), "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_add_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_add_return\n\
add %0,%1,%0\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
SMP_ISYNC
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
static __inline__ void atomic_sub(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%3 # atomic_sub\n\
subf %0,%2,%0\n"
PPC405_ERR77(0,%3)
" stwcx. %0,0,%3 \n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (a), "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_sub_return(int a, atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_sub_return\n\
subf %0,%1,%0\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
SMP_ISYNC
: "=&r" (t)
: "r" (a), "r" (&v->counter)
: "cc", "memory");
return t;
}
static __inline__ void atomic_inc(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_inc\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%2)
" stwcx. %0,0,%2 \n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_inc_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%1 # atomic_inc_return\n\
addic %0,%0,1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1 \n\
bne- 1b"
SMP_ISYNC
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
static __inline__ void atomic_dec(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%2 # atomic_dec\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%2)\
" stwcx. %0,0,%2\n\
bne- 1b"
: "=&r" (t), "=m" (v->counter)
: "r" (&v->counter), "m" (v->counter)
: "cc");
}
static __inline__ int atomic_dec_return(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%1 # atomic_dec_return\n\
addic %0,%0,-1\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1\n\
bne- 1b"
SMP_ISYNC
: "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return((v)) == 0)
/*
* Atomically test *v and decrement if it is greater than 0.
* The function returns the old value of *v minus 1.
*/
static __inline__ int atomic_dec_if_positive(atomic_t *v)
{
int t;
__asm__ __volatile__(
"1: lwarx %0,0,%1 # atomic_dec_if_positive\n\
addic. %0,%0,-1\n\
blt- 2f\n"
PPC405_ERR77(0,%1)
" stwcx. %0,0,%1\n\
bne- 1b"
SMP_ISYNC
"\n\
2:" : "=&r" (t)
: "r" (&v->counter)
: "cc", "memory");
return t;
}
#define __MB __asm__ __volatile__ (SMP_SYNC : : : "memory")
#define smp_mb__before_atomic_dec() __MB
#define smp_mb__after_atomic_dec() __MB
#define smp_mb__before_atomic_inc() __MB
#define smp_mb__after_atomic_inc() __MB
#endif /* __KERNEL__ */
#endif /* _ASM_PPC_ATOMIC_H_ */
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